SCUDDEE ON TERTIARY INSECTS. 523 



indications of an inferior as well as an earlier type, while no such con- 

 trast is presented in the delicate shading and more complicated pat- 

 tern of the hind wings. But, again, a partial comparison may be made 

 with the markings of the front wing alone, and in the seven other species 

 €f described fossil butterflies there is not one, with the possible excep- 

 tion of Eugonia atava* (Heer) Scudd., in which the markings may be 

 looked upon as less highly developed than in the living types. 



Instances could, of course, be easily given from among living types 

 in which the ornamentation of the upper surface is less variegated in the 

 fore wings than in the hind pair, but it might readily be doubted 

 whether this should be looked upon as having any direct bearing upon 

 this subject; yet, even if none could be cited, it may fairly be urged 

 that the lapse of time since the Florissant beds were deposited is am- 

 ply suflicient for the loss of any such indication of hesperidiform affini- 

 ties in a group of insects so pliable in ornamentation as butterflies are 

 shown to be by the mere facts of mimicry. 



Prodryas shows further peculiarities when compared with its nearest 

 living allies. In the Tropical American genus Sypanartia, which seems 

 to be its nearest neighbor, as in all those closely allied to it at the pres- 

 ent day, the costal margin beyond the base is uniformly arched through- 

 out ; and the outer margin, angulated in the upper half of the wing, is 

 roundly excised below it, giving these butterflies the common name of 

 " angle wings ". They are insects of strong and rapid flight, capable of the 

 most abrupt and unanticipated mjovements, making them very difficult 

 of capture on the wing. The straight, strong costa and more elongated 

 wing of Prodryas, on the other hand, with its nearly uniform straight, 

 outer border, combined with the robustness of the body, indicate great 

 strength of wing and a rapid direct flight, as i!i the Hesperides, but not 

 the power of sudden turning. 



InifT/i'ftWft^'^^'rtanditsimmediateallies, the cell of the front wing is closed, 

 although by a feeble vein, and the superior subcostal nervules take their 

 rise at more or less irregular distances apart, and run long distances 

 crowded side by side ; while in Prodryas the cell is open, and the sub- 

 costal nervules are much shorter and very uniform in their distribution ; 

 the inferior subcostal nervules also originate in Prodryas in a much 

 simpler fashion, indicating that its ancestors never had the cell closed, 

 although a foreshadowing of the closure may be seen in a row of special 

 scales (or a line of color) at the supposititious termination of the cell. 

 That this can hardly indicate a true vein appears from the fact that 

 there is not the slightest tendency of the opposing veins to approach 

 each other at its extremities — a tendency which it would seem should 

 naturally precede the formation of a vein ; the second inferior subcostal 

 nervule takes its rise from the first in just about the same manner as 



* The remnant of this insect's front wing is certainly simpler in markings than the 

 npper surface of allied living Eugonias, but it may represent an inferior surface, in 

 ■which case there is no special difference. 



